Catalyst containing γ-valerolactone and/or the hydrolysis products thereof, and use thereof in a hydroprocessing and/or hydrocracking method

ABSTRACT

The invention relates to a catalyst comprising a support based on alumina or silica or silica-alumina, at least one element of group VIII, at least one element of group VIB and at least one additive selected from γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid. The invention also relates to the process for the preparation of said catalyst and the use thereof in a hydrotreatment and/or hydrocracking process.

The invention relates to a catalyst with the additives γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid and/or4-pentenoic acid, the method for the preparation thereof and the usethereof in the field of hydrotreatment and/or hydrocracking.

A catalyst for the hydrotreatment of hydrocarbon-containing cuts usuallyhas the aim of removing the sulphur-containing or nitrogen-containingcompounds contained therein so that for example a petroleum productmeets the required specifications (sulphur content, aromatics contentetc.) for a given application (motor fuel, gasoline or gasoil, domesticfuel oil, jet fuel). It may also be a question of pre-treating thisfeedstock in order to remove impurities from it or to hydrogenate itbefore subjecting it to various conversion processes for modifying itsphysicochemical properties, such as for example processes of reforming,hydrocracking of vacuum distillates, catalytic cracking, hydroconversionof atmospheric or vacuum residues. The composition and the use ofhydrotreatment catalysts are described particularly well in the articleby B. S. Clausen, H. T. Topsøe, and F. E. Massoth, from the workCatalysis Science and Technology, volume 11 (1996), Springer-Verlag.

Stricter vehicle pollution standards in the European Community (OfficialJournal of the European Union, L76, 22 Mar. 2003, Directive 2003/70/CE,pages L76/10-L76/19) have compelled refiners to dramatically reduce thesulphur content of diesel fuels and gasolines (to a maximum of 10 partsper million by weight (ppm) of sulphur on 1 Jan. 2009, against 50 ppm on1 Jan. 2005). Moreover, the refiners are compelled to use feedstocksthat are more and more refractory to hydrotreatment processes on the onehand because the crude oils are becoming increasingly heavy andconsequently contain an increasing amount of impurities, and on theother hand owing to the increasing use of conversion processes inrefineries. In fact, these generate cuts that are more difficult tohydrotreat than the cuts originating directly from atmosphericdistillation. By “more difficult to hydrotreat” is usually meant higheroperating temperatures to achieve the same sulphur content in theeffluent, and consequently cycle times that can be reduced.

These feedstocks require catalysts having hydrodesulphurizing andhydrogenating functions that are greatly improved with respect toconventional catalysts.

Moreover, conversion processes such as catalytic cracking orhydrocracking use catalysts having an acid function, which makes themparticularly sensitive to the presence of nitrogen-containingimpurities, and especially basic nitrogen-containing compounds. It istherefore necessary to use catalysts for pre-treatment of thesefeedstocks so as to remove these compounds.

Conventional hydrotreatment catalysts generally comprise an oxidesupport and an active phase based on metals of groups VIB and VIII intheir oxide forms, as well as phosphorus. Preparation of these catalystsgenerally comprises a step of impregnation of the metals and of thephosphorus on the support, followed by drying and calcination making itpossible to obtain the active phase in their oxide forms. Before theyare used in a hydrotreatment and/or hydrocracking reaction, thesecatalysts are generally subjected to sulphurization in order to form theactive species.

The addition of an organic compound to hydrotreatment catalysts in orderto improve their activity has been recommended by a person skilled inthe art, in particular for catalysts that have been prepared byimpregnation followed by drying without subsequent calcination. Thesecatalysts are often called “additive-impregnated dried catalysts”.

Many documents describe the use of various ranges of organic compoundsas additives, such as nitrogen-containing organic compounds and/oroxygen-containing organic compounds.

A family of compounds that is now well known from the literature is thechelating nitrogen-containing compounds (EP0181035, EP1043069 and U.S.Pat. No. 6,540,908) with, by way of example, ethylenediaminetetraaceticacid (EDTA), ethylenediamine, diethylenetriamine or nitrilotriaceticacid (NTA).

In the family of organic compounds containing oxygen, the use of mono-,di- or polyols, optionally etherified, is described in documentsWO96/41848, WO01/76741, U.S. Pat. Nos. 4,012,340, 3,954,673, EP601722,and WO2005/035691. More rarely, the prior art mentions additivescomprising ester functions (EP1046424, WO2006/077326).

There are also several patents that claim the use of carboxylic acids(EP1402948, EP0482817). In particular, in document EP0482817, citricacid, but also tartaric, butyric, hydroxyhexanoic, malic, gluconic,glyceric, glycolic, hydroxybutyric acids have been described. Thespecificity is based on the drying, which must be carried out at atemperature of less than 200° C.

Document US2014/0305842 describes the use of heterocyclic compoundscontaining oxygen or nitrogen in the ring, such as lactams,oxacycloalkanes or lactones. In particular with regard to lactones, thisdocument mentions β-propriolactone, γ-butyrolactone and δ-valerolactone.

However, none of the documents relating to the additives describes theuse of γ-valerolactone, or even of 4-hydroxyvaleric acid or 2-pentenoicacid, 3-pentenoic acid or 4-pentenoic acid, which may be obtaineddirectly or indirectly by hydrolysis of γ-valerolactone.

Whatever compounds are selected, the modifications induced do not alwaysmake it possible to increase catalyst performance sufficiently to meetthe specifications relating to the sulphur and/or nitrogen contents ofmotor fuels. Moreover, it is often very complicated to apply themindustrially, as the methods are complex to implement.

Consequently, it proves to be essential for catalyst manufacturers tofind new hydrotreatment and/or hydrocracking catalysts with improvedperformance.

SUMMARY

The invention relates to a catalyst comprising a support based onalumina or silica or silica-alumina, at least one element of group VIII,at least one element of group VIB and at least one additive selectedfrom γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,3-pentenoic acid or 4-pentenoic acid.

The applicant in fact found that the use of at least one additiveselected from γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,3-pentenoic acid or 4-pentenoic acid as organic additive(s) on acatalyst containing at least one element of group VIII and at least oneelement of group VIB allowed a hydrotreatment and/or hydrocrackingcatalyst with improved catalytic performance to be obtained.

In fact, the catalyst according to the invention shows increasedactivity with respect to the catalysts without additives and to theknown dried catalysts with additives. Typically, owing to the increasein activity, the temperature required to reach a desired sulphur ornitrogen content (for example 10 ppm of sulphur in the case of a gasoilfeedstock, in ULSD or Ultra Low Sulphur Diesel mode) may be lowered.Moreover, stability is increased, as the cycle time is prolonged due tothe decrease in the required temperature.

The catalyst according to the present invention is moreover easy toprepare due to the high solubility of γ-valerolactone, 4-hydroxyvalericacid, 2-pentenoic acid, 3-pentenoic acid and 4-pentenoic acid in wateror any other polar protic solvent.

Furthermore, the catalyst according to the invention may be preparedfrom a raw material originating from biomass preferably containingpredominantly γ-valerolactone (J-C. Serrano-Ruiz in Green Chem., 2010,12, 574-577, or W. R. H. Wright and R. Palkovits in ChemSusChem 2012, 5,9, 1657-1667) while remaining at an acceptable cost price.

According to a variant, the content of an element of group VIB isbetween 5 and 40% by weight expressed as oxide of a metal of group VIBwith respect to the total weight of the catalyst, and the content of anelement of group VIII is comprised between 1 and 10% by weight expressedas oxide of a metal of group VIII with respect to the total weight ofthe catalyst.

According to a variant, the molar ratio of the element of group VIII tothe element of group VIB in the catalyst is comprised between 0.1 and0.8.

According to a variant, the catalyst additionally contains phosphorus,the phosphorus content being comprised between 0.1 and 20% by weightexpressed as P₂O₅ with respect to the total weight of the catalyst andthe ratio of phosphorus to the element of group VIB in the catalyst isgreater than or equal to 0.05.

According to a variant, the total content of additive(s) selected fromγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid is comprised between 1 and 35% by weight withrespect to the total weight of the catalyst.

According to a variant, the catalyst additionally contains an organiccompound other than the additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid, said organic compound containing oxygen and/or nitrogen and/orsulphur. According to this variant, the organic compound is preferablyselected from a compound comprising one or more chemical functionsselected from a carboxyl, alcohol, thiol, thioether, sulphone,sulphoxide, ether, aldehyde, ketone, ester, carbonate, amine, nitrile,imide, oxime, urea and amide function. Preferably, it is selected fromtriethylene glycol, diethylene glycol, ethylenediaminetetraacetic acid(EDTA), maleic acid, citric acid, dimethylformamide, bicine, or tricine.

According to a variant, the support contains from 0.1 to 50% by weightof zeolite.

According to a variant, the catalyst is at least partially sulphurized.

The invention also relates to the process for the preparation of saidcatalyst comprising the following steps:

-   -   a) bringing at least one component of an element of group VIB,        at least one component of an element of group VIII, at least one        additive selected from γ-valerolactone, 4-hydroxyvaleric acid,        2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid and        optionally phosphorus into contact with a support based on        alumina or silica or silica-alumina, or bringing a regenerated        catalyst containing a support based on alumina or silica or        silica-alumina, at least one component of an element of group        VIB, at least one component of an element of group VIII and        optionally phosphorus into contact with at least one additive        selected from γ-valerolactone, 4-hydroxyvaleric acid,        2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid, so as to        obtain a catalyst precursor,    -   b) drying said catalyst precursor originating from step a) at a        temperature of less than 200° C., without calcining it        subsequently.

According to a variant, step a) is the following step:

-   -   a′) impregnating a support based on alumina or silica or        silica-alumina with at least one solution containing at least        one element of group VIB, at least one element of group VIII, at        least one additive selected from γ-valerolactone,        4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or        4-pentenoic acid and optionally phosphorus so as to obtain a        catalyst precursor.

According to another variant, step a) comprises the following steps:

-   -   a1) impregnating a support based on alumina or silica or        silica-alumina with at least one solution containing at least        one element of group VIB, at least one element of group VIII and        optionally phosphorus in order to obtain an impregnated support,    -   a2) drying the impregnated support obtained in step a1) at a        temperature of less than 200° C. in order to obtain a dried        impregnated support, and optionally calcining the dried        impregnated support in order to obtain a calcined impregnated        support,    -   a3) impregnating the dried and optionally calcined impregnated        support obtained in step a2) with an impregnating solution        comprising at least one additive selected from γ-valerolactone,        4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or        4-pentenoic acid so as to obtain a catalyst precursor,    -   a4) optionally, leaving the catalyst precursor obtained in step        a3) to mature.

According to another variant, step a) comprises the following steps:

-   -   a1′) preparing a support comprising at least one additive        selected from γ-valerolactone, 4-hydroxyvaleric acid,        2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid and        optionally at least one part of phosphorus,    -   a2′) impregnating the support obtained in step a1′) with an        impregnating solution comprising at least one element of group        VIB, at least one element of group VIII and optionally        phosphorus so as to obtain a catalyst precursor,    -   a3′) optionally, leaving the catalyst precursor obtained in step        a2′) to mature.

According to another variant, step a) comprises the following steps:

-   -   a1″) by co-impregnation, bringing a solution containing at least        one element of group VIB, at least one element of group VIII, at        least one organic compound containing oxygen and/or nitrogen        and/or sulphur, and optionally phosphorus into contact with a        support based on alumina or silica or silica-alumina so as to        obtain an impregnated support,    -   a2″) drying the impregnated support originating from step a1″)        at a temperature of less than 200° C., without calcining it        subsequently, in order to obtain a dried impregnated support,    -   a3″) bringing the dried impregnated support originating from        step a2″) into contact with a solution of an organic compound        containing oxygen and/or nitrogen and/or sulphur, identical to        or different from that used in step a1″) so as to obtain a        catalyst precursor,    -   a4″) optionally, leaving the catalyst precursor obtained in step        a3″) to mature,    -   and at least one of the organic compounds in step a1″) or in        step a3″) is selected from γ-valerolactone, 4-hydroxyvaleric        acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid.

According to a variant, when it is desired to prepare the catalystaccording to the invention starting from a regenerated catalyst, step a)of the preparation process comprises the following steps:

-   -   a1′″) impregnating a regenerated catalyst containing a support        based on alumina or silica or silica-alumina, at least one        component of an element of group VIB, at least one component of        an element of group VIII and optionally phosphorus with an        impregnating solution comprising at least one additive selected        from γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,        3-pentenoic acid or 4-pentenoic acid so as to obtain a catalyst        precursor,    -   a2′″) optionally, leaving the catalyst precursor obtained in        step a1′″) to mature.

According to a variant, the total molar ratio of the additive(s)selected from γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,3-pentenoic acid or 4-pentenoic acid per element(s) of group VIII iscomprised between 0.1 and 5.0 mol/mol.

The invention also relates to the use of the catalyst according to theinvention or prepared by the preparation process according to theinvention in a process for hydrotreatment and/or hydrocracking ofhydrocarbon-containing cuts.

Hereinafter, the groups of chemical elements are given according to theCAS classification (CRC Handbook of Chemistry and Physics, publisher CRCPress, chief editor D. R. Lide, 81st edition, 2000-2001). For example,group VIII according to the CAS classification corresponds to the metalsof columns 8, 9 and 10 according to the new IUPAC classification.

By “hydrotreatment” is meant reactions including in particularhydrodesulphurization (HDS), hydrodenitrogenation (HDN) andhydrogenation of aromatics (HDA).

DETAILED DESCRIPTION OF THE INVENTION

Catalyst

The catalyst according to the invention is an additive catalystcontaining at least one additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid. More particularly, the catalyst according to the inventioncomprises a support based on alumina or silica or silica-alumina, atleast one element of group VIII, at least one element of group VIB andat least one additive selected from γ-valerolactone, 4-hydroxyvalericacid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid.

The catalyst according to the invention may be a fresh catalyst, i.e. acatalyst that has not been used previously as a catalyst in a catalyticunit and in particular in hydrotreatment and/or hydrocracking.

The catalyst according to the invention may also be a rejuvenatedcatalyst. By rejuvenated catalyst is meant a catalyst that has been usedas a catalyst in a catalytic unit and in particular in hydrotreatmentand/or hydrocracking and that has undergone at least one step ofcalcination in order to burn off the coke (regeneration). Then at leastone additive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid is added to thisregenerated catalyst in order to obtain the rejuvenated catalyst. Thisrejuvenated catalyst may contain one or more other organic additive(s)which may be added before, after or at the same time as the additive oradditives selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid.

The hydrogenating function of said catalyst, also called the activephase, is ensured by at least one element of group VIB and at least oneelement of group VIII.

The preferred elements of group VIB are molybdenum and tungsten. Thepreferred elements of group VIII are non-noble elements and inparticular cobalt and nickel.

Advantageously, the hydrogenating function is selected from the groupcomprising combinations of the elements cobalt-molybdenum,nickel-molybdenum, nickel-tungsten or nickel-cobalt-molybdenum, ornickel-molybdenum-tungsten.

In the case where a high activity in hydrodesulphurization, or inhydrodenitrogenation and in hydrogenation of aromatics is desired, thehydrogenating function is advantageously provided by the combination ofnickel and molybdenum; a combination of nickel and tungsten in thepresence of molybdenum may also be advantageous. In the case offeedstocks of the vacuum distillate type or heavier feedstocks,combinations of the cobalt-nickel-molybdenum type may advantageously beused.

The total content of elements of group VIB and group VIII isadvantageously greater than 6% by weight expressed as oxide with respectto the total weight of the catalyst.

The content of an element of group VIB is comprised between 5 and 40% byweight, preferably between 8 and 35% by weight, and more preferablybetween 10 and 30% by weight expressed as oxide of a metal of group VIBwith respect to the total weight of the catalyst.

The content of an element of group VIII is comprised between 1 and 10%by weight, preferably between 1.5 and 9% by weight, and more preferablybetween 2 and 8% by weight expressed as oxide of a metal of group VIIIwith respect to the total weight of the catalyst.

The molar ratio of an element of group VIII to an element of group VIBin the catalyst is preferably comprised between 0.1 and 0.8, preferablycomprised between 0.15 and 0.6 and even more preferably comprisedbetween 0.2 and 0.5.

The catalyst according to the invention advantageously also comprisesphosphorus as a dopant. A dopant is an element that is added, which initself does not have any catalytic character but which increases thecatalytic activity of the active phase.

The phosphorus content in said catalyst is preferably comprised between0.1 and 20% by weight expressed as P₂O₅, preferably between 0.2 and 15%by weight expressed as P₂O₅, and very preferably between 0.3 and 10% byweight expressed as P₂O₅.

The molar ratio of phosphorus to the element of group VIB in thecatalyst is greater than or equal to 0.05, preferably greater than orequal to 0.07, preferably comprised between 0.08 and 1, preferablycomprised between 0.08 and 0.7 and very preferably comprised between0.08 and 0.5.

The catalyst according to the invention may advantageously furthercontain at least one dopant selected from boron, fluorine and a mixtureof boron and fluorine.

When the catalyst contains boron, the boron content is preferablycomprised between 0.1 and 10% by weight expressed as boron oxide,preferably between 0.2 and 7% by weight, and very preferably comprisedbetween 0.2 and 5% by weight.

When the catalyst contains fluorine, the fluorine content is preferablycomprised between 0.1 and 10% by weight expressed as fluorine,preferably between 0.2 and 7% by weight, and very preferably comprisedbetween 0.2 and 5% by weight.

When the catalyst contains boron and fluorine, the total content ofboron and fluorine is preferably comprised between 0.1 and 10% by weightexpressed as boron oxide and fluorine, preferably between 0.2 and 7% byweight, and very preferably comprised between 0.2 and 5% by weight.

The catalyst according to the invention comprises a support based onalumina or silica or silica-alumina.

When the support of said catalyst is based on alumina, it contains morethan 50% of alumina, and generally it contains only alumina orsilica-alumina as defined below.

Preferably, the support comprises alumina, and preferably extrudedalumina.

Preferably, the alumina is gamma alumina.

The alumina support advantageously has a total pore volume comprisedbetween 0.1 and 1.5 cm³·g⁻¹, preferably between 0.4 and 1.1 cm³·g⁻¹. Thetotal pore volume is measured by mercury porosimetry according tostandard ASTM D4284 with a wetting angle of 140°, as described in thework by Rouquerol F.; Rouquerol J.; Singh K. “Adsorption by Powders &Porous Solids: Principle, methodology and applications”, Academic Press,1999, for example by means of the model Autopore III™ apparatus with thetrade mark Micromeritics™.

The specific surface area of the alumina support is advantageouslycomprised between 5 and 400 m²·g⁻¹, preferably between 10 and 350m²·g⁻¹, more preferably between 40 and 350 m²·g^(−1.). The specificsurface area is determined in the present invention by the BET methodaccording to standard ASTM D3663; this method is described in the samework cited above.

In another preferred case, the support of said catalyst is asilica-alumina containing at least 50% by weight of alumina. The silicacontent of the support is at most 50% by weight, most often less than orequal to 45% by weight, preferably less than or equal to 40% by weight.

The sources of silicon are well known to a person skilled in the art. Byway of example silicic acid, silica in the form of powder or incolloidal form (silica sol), and tetraethylorthosilicate Si(OEt)₄ may bementioned.

When the support of said catalyst is based on silica, it contains morethan 50% by weight of silica, and generally it only contains silica.

According to a particularly preferred variant, the support consists ofalumina, silica or silica-alumina.

The support may also advantageously further contain from 0.1 to 50% byweight of zeolite. In this case, all the sources of zeolite and all theassociated methods of preparation known to a person skilled in the artmay be incorporated. Preferably, the zeolite is selected from the groupFAU, BEA, ISV, IWR, IWW, MEI, UWY, and preferably the zeolite isselected from the group FAU and BEA, such as zeolite Y and/or beta.

In certain particular cases, the support may also contain at least onepart of the VIB and VIII metal (metals), and/or at least one part of thedopant(s) including phosphorus and/or at least one part of the organiccompound(s) containing oxygen (at least one additive selected fromγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid or another additive containing oxygen) and/ornitrogen and/or sulphur that were introduced outside of the operationsof impregnation (introduced for example during preparation of thesupport).

The support is advantageously in the form of beads, extrudates, pellets,or irregular, non-spherical agglomerates, the specific form of which mayresult from a crushing step.

The catalyst according to the invention also comprises at least oneadditive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid. Theγ-valerolactone, 4-hydroxyvaleric acid and the 2-pentenoic, 3-pentenoicand 4-pentenoic acids correspond respectively to the following formulae(a), (b), (c), (d) and (e) described below:

The 2-pentenoic acid and 3-pentenoic acid may be in the form of the E orZ isomer or a mixture of these two isomers.

The presence of at least one additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid on the catalyst gives increased activity with respect to thecatalysts without additives and the known dried catalysts withadditives.

Without being bound by any theory, it should be noted that4-hydroxyvaleric acid or 2-pentenoic acid, 3-pentenoic acid or4-pentenoic acid may be obtained directly or indirectly by hydrolysis ofγ-valerolactone. In fact, γ-valerolactone can generate 4-hydroxyvalericacid by hydrolysis as suggested in the works by Raghunath V. Chaudhariin Top Catal (2012) 55:439-445 or by William N. Fishbein and Samuel P.Bessman in The Journal of Biological Chemistry, Vol. 241, No. 21, issueof November 10, pp. 4842-4847, 1966. The latter may then be dehydratedin an acid medium (Langmuir, 2010, 26 (21), pp 16291-16298 by J. Q.Bond, D. M. Alonso, R. M. West, and J. A. Dumesic) leading to a mixtureof 2-pentenoic acid, 3-pentenoic acid and/or 4-pentenoic acid.

According to a variant, the presence of at least one additive selectedfrom γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,3-pentenoic acid and/or 4-pentenoic acid on the catalyst may be due tothe addition as such of the additive(s), alone or in a mixture.

According to another variant, the presence of at least one additiveselected from 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acidand/or 4-pentenoic acid on the catalyst may be due to hydrolysis of theγ-valerolactone contained in the impregnating solution added to saidcatalyst precursor or support and optionally a subsequent step ofdehydration.

The total content of additive(s) selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid and/or4-pentenoic acid on the catalyst according to the invention is comprisedbetween 1 and 35% by weight, preferably between 2 and 30% by weight, andmore preferably between 3 and 25% by weight with respect to the totalweight of the catalyst. During preparation of the catalyst, the step orsteps of drying following introduction of the additive(s) is (are)carried out at a temperature of less than 200° C. so as preferably toretain at least 30%, preferably at least 50%, and very preferably atleast 70% of the quantity of additive(s) introduced, calculated on thebasis of the carbon remaining on the catalyst.

The catalyst according to the invention may comprise, in addition to theadditive(s) selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid and/or 4-pentenoic acid, anotherorganic compound or a group of organic compounds known for their role asadditives. The function of the additives is to increase the catalyticactivity, with respect to the catalysts without additives.

In the remainder of the text, by “said additives” is meant at least oneadditive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid.

More particularly, the catalyst according to the invention may furthercomprise one or more organic compounds containing oxygen other than saidadditives and/or one or more organic compounds containing nitrogenand/or one or more organic compounds containing sulphur. Preferably, thecatalyst according to the invention may further comprise one or moreorganic compounds containing oxygen other than said additives, and/orone or more organic compounds containing nitrogen.

Preferably, the organic compound contains at least 2 carbon atoms and atleast one oxygen and/or nitrogen atom.

Generally, the organic compound is selected from a compound comprisingone or more chemical functions selected from a carboxyl, alcohol, thiol,thioether, sulphone, sulphoxide, ether, aldehyde, ketone, ester,carbonate, amine, nitrile, imide, oxime, urea and amide function.Preferably, the organic compound is selected from a compound comprisingtwo alcohol functions and/or two carboxyl functions and/or two esterfunctions and/or at least one amide function.

The organic compound containing oxygen may be one or more selected fromthe compounds comprising one or more chemical functions selected from acarboxyl, alcohol, ether, aldehyde, ketone, ester or carbonate function.By way of example, the organic compound containing oxygen may be one ormore selected from the group constituted by ethylene glycol, diethyleneglycol, triethylene glycol, a polyethylene glycol (with a molecularweight comprised between 200 and 1500 g/mol), propylene glycol,2-butoxyethanol, 2-(2-butoxyethoxy)ethanol, 2-(2-methoxyethoxy)ethanol,triethyleneglycol dimethyl ether, glycerol, acetophenone,2,4-pentanedione, pentanone, acetic acid, maleic acid, malic acid,malonic acid, malic acid, oxalic acid, gluconic acid, tartaric acid,citric acid, γ-ketovaleric acid, a C₁-C₄ dialkyl succinate, methylacetoacetate, a lactone, dibenzofuran, a crown ether, orthophthalicacid, glucose and propylene carbonate.

The organic compound containing nitrogen may be one or more selectedfrom the compounds comprising one or more chemical functions selectedfrom an amine or nitrile function. By way of example, the organiccompound containing nitrogen may be one or more selected from the groupconstituted by ethylenediamine, diethylenetriamine,hexamethylenediamine, triethylenetetramine, tetraethylenepentamine,pentaethylenehexamine, acetonitrile, octylamine, guanidine or acarbazole.

The organic compound containing oxygen and nitrogen may be one or moreselected from the compounds comprising one or more chemical functionsselected from a carboxylic acid, alcohol, ether, aldehyde, ketone,ester, carbonate, amine, nitrile, imide, amide, urea or oxime function.By way of example, the organic compound containing oxygen and nitrogenmay be one or more selected from the group constituted by1,2-cyclohexanediaminetetraacetic acid, monoethanolamine (MEA),N-methylpyrrolidone, dimethylformamide, ethylenediaminetetraacetic acid(EDTA), alanine, glycine, nitrilotriacetic acid (NTA),N-(2-hydroxyethyl)ethylenediamine-N,N′,N′-triacetic acid (HEDTA),diethylenetriaminepentaacetic acid (DTPA), tetramethylurea, glutamicacid, dimethylglyoxime, bicine or tricine, or a lactam.

The organic compound containing sulphur may be one or more selected fromthe compounds comprising one or more chemical functions selected from athiol, thioether, sulphone or sulphoxide function. By way of example,the organic compound containing sulphur may be one or more selected fromthe group constituted by thioglycolic acid,2-hydroxy-4-methylthiobutanoic acid, a sulphonated derivative of abenzothiophene or a sulphoxidized derivative of a benzothiophene.

Preferably, the organic compound contains oxygen, and preferably it isselected from triethylene glycol, diethylene glycol,ethylenediaminetetraacetic acid (EDTA), maleic acid, citric acid,dimethylformamide, bicine, or tricine.

When it (they) is/are present, the total content of organic compound(s)with additive function (other than said additives) containing oxygenand/or nitrogen and/or sulphur on the catalyst according to theinvention is comprised between 1 and 30% by weight, preferably between1.5 and 25% by weight, and more preferably between 2 and 20% by weightwith respect to the total weight of the catalyst.

Preparation Process

The catalyst according to the invention may be prepared by any processfor the preparation of a supported catalyst with an organic compound asadditive known to a person skilled in the art.

The catalyst according to the invention may be prepared by a preparationprocess comprising the following steps:

-   -   a) bringing at least one component of an element of group VIB,        at least one component of an element of group VIII, at least one        additive selected from γ-valerolactone, 4-hydroxyvaleric acid,        2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid and        optionally phosphorus into contact with a support based on        alumina or silica or silica-alumina, or bringing a regenerated        catalyst containing a support based on alumina or silica or        silica-alumina, at least one component of an element of group        VIB, at least one component of an element of group VIII and        optionally phosphorus into contact with at least one additive        selected from γ-valerolactone, 4-hydroxyvaleric acid,        2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid, so as to        obtain a catalyst precursor,    -   b) drying said catalyst precursor originating from step a) at a        temperature of less than 200° C., without calcining it        subsequently.

First, the process for the preparation of a fresh catalyst will bedescribed, and after that, the process for the preparation of arejuvenated catalyst.

Process for the Preparation of a Fresh Catalyst

The contacting step a) comprises several embodiments, which differ inparticular by the time of introduction of the additive selected fromγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid, which may be carried out either at the sametime as impregnation of the metals (co-impregnation), or afterimpregnation of the metals (post-impregnation), or finally beforeimpregnation of the metals (pre-impregnation). Moreover, the contactingstep may combine at least two embodiments, for example co-impregnationand post-impregnation. These various embodiments will be describedlater. Each embodiment, alone or in combination, may take place in oneor more steps.

It is important to emphasize that during its preparation process, thecatalyst according to the invention does not undergo calcination afterintroduction of the additive or additives selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid or any other organic compound containing oxygen and/or nitrogenand/or sulphur in order to preserve, at least partly, the additive oradditives selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid or any otherorganic compound in the catalyst. By calcination is meant here a heattreatment under a gas containing air or oxygen at a temperature greaterthan or equal to 200° C.

However, the catalyst precursor may undergo a calcining step before theintroduction of at least one additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid or any other organic compound containing oxygen and/or nitrogenand/or sulphur, in particular after impregnation of the elements ofgroup VIB and VIII (post-impregnation) optionally in the presence ofphosphorus and/or of another dopant or during regeneration of a catalystthat has already been used. The hydrogenating function comprising theelements of group VIB and group VIII of the catalyst according to theinvention, also called the active phase, is then in an oxide form.

According to another variant, the catalyst precursor does not undergo acalcining step after impregnation of the elements of group VIB and VIII(post-impregnation), it is simply dried. The hydrogenating functioncomprising the elements of group VIB and group VIII of the catalystaccording to the invention, also called the active phase, is not then inan oxide form.

Whatever the embodiment, the contacting step a) generally comprises atleast one step of impregnation, preferably a step of dry impregnation,in which the support is impregnated with an impregnating solutioncomprising at least one element of group VIB, at least one element ofgroup VIII, and optionally phosphorus. In the case of co-impregnation,described in detail below, this impregnating solution further comprisesat least one additive selected from γ-valerolactone, 4-hydroxyvalericacid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid. Theelements of group VIB and group VIII are generally introduced byimpregnation, preferably by dry impregnation or by impregnation withexcess solution. Preferably, all of the elements of group VIB and groupVIII are introduced by impregnation, preferably by dry impregnation,regardless of the embodiment.

The elements of group VIB and group VIII may also be introduced partlyduring forming said support at the time of mixing with at least onealumina gel selected as matrix, the rest of the hydrogenating elementsthen being introduced subsequently by impregnation. Preferably, when theelements of group VIB and group VIII are introduced partly at the timeof mixing, the proportion of the element of group VIB introduced duringthis step is less than 5% by weight of the total quantity of the elementof group VIB introduced on the final catalyst.

Preferably, the element of group VIB is introduced at the same time asthe element of group VIII, regardless of the method of introduction.

The molybdenum precursors that may be used are well known to a personskilled in the art. For example, among the sources of molybdenum, theoxides and hydroxides, the molybdic acids and salts thereof can be used,in particular the ammonium salts such as ammonium molybdate, ammoniumheptamolybdate, phosphomolybdic acid (H₃PMo₁₂O₄₀) and salts thereof, andoptionally silicomolybdic acid (H₄SiMo₁₂O₄₀) and salts thereof. Thesources of molybdenum may also be heteropoly compounds of the Keggin,Iacunar Keggin, substituted Keggin, Dawson, Anderson, or Strandbergtype, for example. Molybdenum trioxide and the heteropolyanions of theStrandberg, Keggin, Iacunar Keggin or substituted Keggin type arepreferably used.

The tungsten precursors that may be used are also well known to a personskilled in the art. For example, among the sources of tungsten, theoxides and hydroxides, the tungstic acids and salts thereof can be used,in particular the ammonium salts such as ammonium tungstate, ammoniummetatungstate, phosphotungstic acid and salts thereof, and optionallysilicotungstic acid (H₄SiW₁₂O₄₀) and salts thereof. The sources oftungsten may also be heteropoly compounds of the Keggin, Iacunar Keggin,substituted Keggin, or Dawson type, for example. The oxides and theammonium salts such as ammonium metatungstate or the heteropolyanions ofthe Keggin, Iacunar Keggin or substituted Keggin type are preferablyused.

The precursors of the elements of group VIII that may be used areadvantageously selected from the oxides, hydroxides, hydroxycarbonates,carbonates and nitrates of the elements of group VIII, for examplenickel hydroxycarbonate, cobalt carbonate or hydroxide are preferablyused.

Phosphorus, when it is present, may be introduced wholly or partly byimpregnation. Preferably, it is introduced by impregnation, preferablydry impregnation, using a solution containing the precursors of theelements of group VIB and group VIII.

Said phosphorus may advantageously be introduced alone or in a mixturewith at least one of the elements of group VIB and group VIII, duringany of the steps for impregnation of the hydrogenating function if thisis introduced in several goes.

Said phosphorus may also be introduced, wholly or partly, during theimpregnation of at least one additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid if this is introduced separately from the hydrogenating function(the case of post- and pre-impregnation described later), and in thepresence or absence of an organic compound containing oxygen and/ornitrogen and/or sulphur other than said additives. It may also beintroduced during synthesis of the support, at any step of the synthesisthereof. It may thus be introduced before, during or after mixing of thealumina gel matrix selected, such as for example and preferably thealumina precursor aluminium oxyhydroxide (boehmite).

The preferred phosphorus precursor is orthophosphoric acid H₃PO₄, butsalts and esters thereof such as the ammonium phosphates are alsosuitable. Phosphorus may also be introduced at the same time as theelement(s) of group VIB in the form of heteropolyanions of the Keggin,Iacunar Keggin, substituted Keggin or Strandberg type.

The additive or additives selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid is/are advantageously introduced into an impregnating solutionwhich, depending on the preparation process, may be the same solution ora different solution from that containing the elements of group VIB andVIII, in a total quantity corresponding to:

-   -   a total molar ratio of the additive(s) selected from        γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,        3-pentenoic acid or 4-pentenoic acid to the element(s) of group        VIB of the catalyst precursor comprised between 0.2 and 2.0        mol/mol, preferably comprised between 0.3 and 1.7 mol/mol,        preferably comprised between 0.5 and 1.5 mol/mol and very        preferably comprised between 0.8 and 1.2 mol/mol, calculated on        the basis of the components introduced into the impregnating        solution(s), and    -   a total molar ratio of the additive(s) selected from        γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,        3-pentenoic acid or 4-pentenoic acid to the element(s) of group        VIII of the catalyst precursor comprised between 0.1 and 5.0        mol/mol, preferably comprised between 0.5 and 4.0 mol/mol,        preferably comprised between 1.0 and 3.0 mol/mol and very        preferably comprised between 1.5 and 3.0 mol/mol, calculated on        the basis of the components introduced into the impregnating        solution(s).

Any impregnating solution described in the present invention maycomprise any polar solvent known to a person skilled in the art. Saidpolar solvent used is advantageously selected from the group formed bymethanol, ethanol, water, phenol, cyclohexanol, used alone or in amixture. Said polar solvent may also be advantageously selected from thegroup formed by propylene carbonate, DMSO (dimethylsulphoxide),N-methylpyrrolidone (NMP) or sulpholane, used alone or in a mixture.Preferably, a polar protic solvent is used. A list of the usual polarsolvents as well as their dielectric constant may be found in the book“Solvents and Solvent Effects in Organic Chemistry” C. Reichardt,Wiley-VCH, 3rd edition, 2003, pages 472-474. Very preferably, thesolvent used is water or ethanol, and particularly preferably thesolvent is water. In a possible embodiment, the solvent may be absentfrom the impregnating solution.

When the catalyst further comprises a dopant selected from boron,fluorine or a mixture of boron and fluorine, introduction of this dopantor these dopants may be done in the same way as the introduction ofphosphorus at various steps of the preparation and in various ways. Saiddopant may advantageously be introduced alone or in a mixture with atleast one of the elements of group VIB and group VIII, during any of thesteps of impregnation of the hydrogenating function if this isintroduced in several goes. Said dopant may also be introduced, whollyor partly, during impregnation of at least one additive selected fromγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid if the latter is introduced separately from thehydrogenating function (the case of post- and pre-impregnation,described later), in the presence or absence of an organic compoundcontaining oxygen and/or nitrogen and/or sulphur other than saidadditives. It may also be introduced from synthesis of the supportonwards, at any step of the synthesis thereof. It may thus be introducedbefore, during or after mixing of the alumina gel matrix selected, suchas for example and preferably the alumina precursor aluminiumoxyhydroxide (boehmite).

Said dopant, when present, is advantageously introduced in a mixturewith the precursor(s) of the elements of group VIB and group VIII,wholly or partly on the formed support by dry impregnation of saidsupport using a solution, preferably aqueous, containing the precursorsof the metals, the phosphorus precursor and the precursor(s) of thedopant(s) (and also containing at least one additive selected fromγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid in the co-impregnation embodiment).

The boron precursors may be boric acid, orthoboric acid H₃BO₃, ammoniumdiborate or pentaborate, boron oxide, boric esters. Boron may beintroduced for example by means of a solution of boric acid in awater/alcohol mixture or also in a water/ethanolamine mixture.Preferably the boron precursor, if boron is introduced, is orthoboricacid.

The fluorine precursors that may be used are well known to a personskilled in the art. For example, the fluoride anions may be introducedin the form of hydrofluoric acid or salts thereof. These salts areformed with alkali metals, ammonium or an organic compound. In thelatter case, the salt is advantageously formed in the reaction mixtureby reaction between the organic compound and hydrofluoric acid.

Fluorine may be introduced for example by impregnation of an aqueoussolution of hydrofluoric acid, or of ammonium fluoride or of ammoniumbifluoride.

When the catalyst further comprises an additional additive (in additionto the additive(s) selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid) or a group ofadditional additives selected from an organic compound containing oxygenand/or nitrogen and/or sulphur other than said additives, this may beintroduced in the impregnating solution in step a).

The total molar ratio of organic compound(s) containing oxygen and/ornitrogen and/or sulphur other than said additives to the elements ofgroup VIB on the catalyst is comprised between 0.05 and 5 mol/mol,preferably comprised between 0.1 and 4 mol/mol, preferably comprisedbetween 0.2 and 3 mol/mol, calculated on the basis of the componentsintroduced into the impregnating solution(s).

The total molar ratio of organic compound(s) containing oxygen and/ornitrogen and/or sulphur other than said additives with respect to thesum of γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,3-pentenoic acid and/or 4-pentenoic acid is comprised between 0.05 and 6mol/mol, preferably comprised between 0.1 and 5 mol/mol, more preferablycomprised between 0.2 and 4 mol/mol, calculated on the basis of thecomponents introduced into the impregnating solution(s).

Advantageously, after each impregnating step, the impregnated support isleft to mature. Maturation allows the impregnating solution to dispersehomogeneously within the support.

Any maturation step described in the present invention is advantageouslycarried out at atmospheric pressure, in a water-saturated atmosphere andat a temperature comprised between 17° C. and 50° C., and preferably atambient temperature. Generally a maturation time comprised between tenminutes and forty-eight hours and preferably comprised between thirtyminutes and five hours is sufficient. Longer times are not excluded, butdo not necessarily provide any improvement.

According to step b) of the preparation process according to theinvention, the catalyst precursor obtained in step a), optionallymatured, is subjected to a drying step at a temperature of less than200° C. without a subsequent calcining step.

Any drying step subsequent to the introduction of said additivesdescribed in the present invention is carried out at a temperature ofless than 200° C., preferably comprised between 50 and 180° C.,preferably between 70 and 150° C. and very preferably between 75 and130° C.

The drying step is advantageously carried out by any technique known toa person skilled in the art. It is advantageously carried out atatmospheric pressure or at reduced pressure. Preferably this step iscarried out at atmospheric pressure. It is advantageously carried out ina transversed bed using air or any other hot gas.

Preferably, when drying is carried out in a fixed bed, the gas used iseither air, or an inert gas such as argon or nitrogen. Very preferably,drying is carried out in a transversed bed in the presence of nitrogenand/or air. Preferably, the drying step is of short duration, comprisedbetween 5 minutes and 4 hours, preferably between 30 minutes and 4 hoursand very preferably between 1 hour and 3 hours.

Drying is then carried out so as preferably to retain at least 30% ofthe additive(s) selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid introduced duringan impregnation step, preferably this quantity is greater than 50% andeven more preferably greater than 70%, calculated on the basis of thecarbon remaining on the catalyst. When an organic compound containingoxygen and/or nitrogen and/or sulphur other than said additives ispresent, the drying step is carried out so as preferably to retain atleast 30%, preferably at least 50%, and very preferably at least 70% ofthe quantity introduced, calculated on the basis of the carbon remainingon the catalyst.

At the end of the drying step b), a dried catalyst is obtained, which isnot subjected to any subsequent calcining step.

Co-impregnation

According to a first embodiment of step a) of the process for thepreparation of the (fresh) catalyst, said components of the elements ofgroup VIB, of the elements of group VIII, of at least one additiveselected from γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,3-pentenoic acid or 4-pentenoic acid and optionally phosphorus aredeposited on said support, by one or more co-impregnation steps, i.e.said components of the elements of group VIB, of group VIII, of at leastone additive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid and optionallyphosphorus are introduced simultaneously into said support(“co-impregnation”). According to a variant, step a) is the followingstep:

-   -   a′) impregnating a support based on alumina or silica or        silica-alumina with at least one solution containing at least        one element of group VIB, at least one element of group VIII, at        least one additive selected from γ-valerolactone,        4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or        4-pentenoic acid and optionally phosphorus so as to obtain a        catalyst precursor.

The co-impregnation step or steps is (are) preferably carried out by dryimpregnation or by impregnation with excess solution. When this firstembodiment comprises the utilization of several co-impregnation steps,each co-impregnation step is preferably followed by an intermediatedrying step at a temperature of less than 200° C., advantageouslycomprised between 50 and 180° C., preferably between 70 and 150° C.,very preferably between 75 and 130° C., optionally observing a period ofmaturation between impregnation and drying.

Very preferably, during preparation by co-impregnation, the elements ofgroup VIB and group VIII, at least one additive selected fromγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid, optionally phosphorus, optionally anotherdopant selected from boron and/or fluorine and optionally an organiccompound containing oxygen and/or nitrogen and/or sulphur other thansaid additives are introduced in step a) entirely after the forming ofsaid support, by dry impregnation of said support using an aqueousimpregnating solution containing the precursors of the elements of groupVIB and group VIII, at least one additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid, optionally the phosphorus precursor, optionally the dopantprecursor selected from boron and/or fluorine and optionally the organiccompound containing oxygen and/or nitrogen and/or sulphur other thansaid additives.

Post-impregnation

According to a second embodiment of step a) of the process for thepreparation of the (fresh) catalyst according to the invention, at leastone additive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid is brought intocontact with a dried and optionally calcined impregnated supportcomprising at least one component of an element of group VIB, at leastone component of an element of group VIII and optionally phosphorus,said support being based on alumina or silica or silica-alumina, so asto obtain a catalyst precursor.

This second embodiment is a preparation by “post-impregnation” of atleast one additive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid. The latter iscarried out for example by dry impregnation.

According to this second embodiment, the contacting according to step a)comprises the following successive steps, which will be described indetail later:

-   -   a1) impregnating a support based on alumina or silica or        silica-alumina with at least one solution containing at least        one element of group VIB, at least one element of group VIII and        optionally phosphorus in order to obtain an impregnated support,    -   a2) drying the impregnated support obtained in step a1) at a        temperature of less than 200° C. in order to obtain a dried        impregnated support, and optionally calcining the dried        impregnated support in order to obtain a calcined impregnated        support,    -   a3) impregnating the dried and optionally calcined impregnated        support obtained in step a2) with an impregnating solution        comprising at least one additive selected from γ-valerolactone,        4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or        4-pentenoic acid so as to obtain a catalyst precursor,    -   a4) optionally, leaving the catalyst precursor obtained in step        a3) to mature.

In step a1) of the embodiment utilizing post-impregnation, theintroduction of the elements of group VIB and group VIII and optionallyphosphorus on the support may advantageously be carried out by one ormore operations of impregnation with excess solution on the support, orpreferably by one or more operations of dry impregnation, and preferablyby a single dry impregnation of said support, using solution(s),preferably aqueous, containing the precursor or precursors of metals andpreferably the phosphorus precursor.

When several impregnation steps are carried out, each impregnation stepis preferably followed by an intermediate drying step at a temperatureof less than 200° C., advantageously between 50 and 180° C., preferablybetween 70 and 150° C., very preferably between 75 and 130° C., andoptionally observing a period of maturation between impregnation anddrying. Each intermediate drying step, prior to the introduction of atleast one additive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid, may be followedby a calcining step under the conditions described below for step a2).

Very preferably, during preparation by post-impregnation, the elementsof group VIB and group VIII and optionally phosphorus, optionallyanother dopant selected from boron and/or fluorine and optionally anorganic compound containing oxygen and/or nitrogen and/or sulphur otherthan said additives are introduced in step a1) entirely after theforming of said support, by dry impregnation of said support using anaqueous impregnating solution containing the precursors of the elementsof group VIB and group VIII, the phosphorus precursor, and optionallythe dopant precursor selected from boron and/or fluorine and optionallythe organic compound containing oxygen and/or nitrogen and/or sulphurother than said additives.

According to another variant, the elements of group VIB and group VIIIand optionally phosphorus, optionally another dopant selected from boronand/or fluorine and optionally an organic compound containing oxygenand/or nitrogen and/or sulphur other than said additives may beintroduced in step a1) successively by means of several impregnatingsolutions containing one or more of the components.

Advantageously, the impregnated support obtained in step a1) is left tomature under the conditions described above for maturation.

According to step a2), the impregnated support obtained in step a1) isdried at a temperature of less than 200° C. in order to obtain animpregnated support, dried under the drying conditions described above.

Optionally, the dried impregnated support may then undergo calcining.Calcining is generally carried out at a temperature comprised between200° C. and 900° C., preferably comprised between 250° C. and 750° C.The calcination time is generally comprised between 0.5 hours and 16hours, preferably between 1 hour and 5 hours. It is generally carriedout under air. Calcining makes it possible to convert the precursors ofthe group VIB and group VIII metals to oxides.

According to step a3), the dried impregnated support obtained in stepa2) is impregnated with an impregnating solution comprising at least oneadditive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid so as to obtain acatalyst precursor.

The additive or additives selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid may advantageously be deposited in one or more steps either byimpregnation in excess, or by dry impregnation, or by any other meansknown to a person skilled in the art.

Preferably, said additive or additives is/are introduced by dryimpregnation, in the presence or absence of a solvent as describedabove.

Preferably, the solvent in the impregnating solution used in step a3) iswater, which facilitates implementation on an industrial scale.

The additive or additives selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid is/are advantageously introduced into the impregnating solution instep a3) with the molar ratios per element of group VIB or of group VIIIdescribed above.

When in addition it is desired to introduce an additional additive (inaddition to the additive(s) selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid) or a group of additional additives selected from an organiccompound containing oxygen and/or nitrogen and/or sulphur other thansaid additives, this may be introduced in the impregnating solution instep a1) and/or into the impregnating solution in step a3) or by anadditional impregnation step at any time in the preparation processbefore the final drying in step b), it being understood that a calciningstep is not carried out after its introduction. This compound isintroduced in the proportions described above.

According to step a4), optionally the catalyst precursor obtained instep a3) is left to mature, under the maturation conditions describedabove.

According to step b) of the preparation process according to theinvention, the catalyst precursor that was optionally matured in stepa4) is subjected to a step of drying at a temperature of less than 200°C. without a subsequent calcining step, as described above.

Pre-impregnation

According to a third embodiment of step a) of the process for thepreparation of the (fresh) catalyst according to the invention, at leastone component of an element of group VIB, at least one component of anelement of group VIII, and optionally phosphorus are brought intocontact with the support based on alumina or silica or silica-aluminathat contains at least one additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid so as to obtain a catalyst precursor.

This third embodiment is a preparation by “pre-impregnation” of at leastone additive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid. This is carriedout for example by dry impregnation.

According to this third embodiment, the contacting according to step a)comprises the following successive steps, which will be described indetail later:

-   -   a1′) preparing a support comprising at least one additive        selected from γ-valerolactone, 4-hydroxyvaleric acid,        2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid and        optionally at least one part of phosphorus,    -   a2′) impregnating the support obtained in step a1′) with an        impregnating solution comprising at least one element of group        VIB, at least one element of group VIII and optionally        phosphorus so as to obtain a catalyst precursor,    -   a3′) optionally, leaving the catalyst precursor obtained in step        a2′) to mature.

In step a1′) of the embodiment utilizing pre-impregnation, a support isprepared comprising at least one additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid and optionally at least one part of phosphorus. The additive oradditives selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid may be introducedat any time in the preparation of the support, and preferably duringforming or by impregnation on a support already formed.

If introduction of at least one additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid on the previously formed support is selected, the latter may becarried out as is indicated for step a3) of post-impregnation. It willthen be followed by an optional maturation step and by drying at atemperature of less than 200° C. under the conditions of maturation anddrying as described above.

If introduction during forming is selected, preferably said forming iscarried out by mixing-extrusion, by pelletization, by the oil-dropmethod, by granulation with a rotating plate or by any other method wellknown to a person skilled in the art. Very preferably, said forming iscarried out by mixing-extrusion, and the γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid and/or4-pentenoic acid may be introduced at any time during mixing-extrusion.The formed material obtained at the end of the forming step thenadvantageously undergoes a step of heat treatment at a temperature suchthat at least a proportion of said additive(s) remains present.

The same applies to the phosphorus optionally present in said support instep a1′).

Phosphorus may be introduced at any time in the preparation of thesupport, and preferably during forming or by impregnation on a supportalready formed as described above. If only phosphorus is introducedduring forming, i.e. without an additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid itself then introduced by impregnation, the calcination temperaturefollowing its introduction may then advantageously be carried out at atemperature of less than 1,000° C.

In step a2′) of the embodiment utilizing pre-impregnation, introductionof the elements of group VIB and group VIII and optionally phosphorusmay advantageously be carried out by one or more impregnations in excesssolution on the support, or preferably by one or more dry impregnations,and preferably by a single dry impregnation of said support, usingsolution(s), preferably aqueous, containing the precursor or precursorsof metals and optionally the phosphorus precursor.

Advantageously, the catalyst precursor obtained in step a2′) is left tomature under the maturation conditions described above.

When in addition it is desired to introduce an additional additive (inaddition to the additive(s) selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid) or a group of additional additives selected from an organiccompound containing oxygen and/or nitrogen and/or sulphur other thansaid additives, this may be introduced into the support in step a1′)during forming or by impregnation, and/or into the impregnating solutionin step a2′) or by an additional impregnation step at any time in thepreparation process before the final drying in step b), it beingunderstood that a calcining step is not carried out after itsintroduction.

The three embodiments described above may be carried out alone asdescribed, or in a mixture in order to give rise to other hybrid methodsof preparation depending on the technical and practical constraints.

According to another alternative embodiment, the contacting according tostep a) combines at least two methods of contacting, for exampleco-impregnation of an organic compound and post-impregnation of anorganic compound, which may be identical to or different from that usedfor co-impregnation, given that at least one of the organic compounds isselected from γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,3-pentenoic acid or 4-pentenoic acid.

According to this alternative embodiment, the contacting according tostep a) comprises the following successive steps:

-   -   a1″) by co-impregnation, bringing a solution containing at least        one element of group VIB, at least one element of group VIII, at        least one organic compound containing oxygen and/or nitrogen        and/or sulphur, and optionally phosphorus into contact with a        support based on alumina or silica or silica-alumina so as to        obtain an impregnated support,    -   a2″) drying the impregnated support originating from step a1″)        at a temperature of less than 200° C., without calcining it        subsequently, in order to obtain a dried impregnated support,    -   a3″) bringing the dried impregnated support originating from        step a2″) into contact with a solution of an organic compound        containing oxygen and/or nitrogen and/or sulphur, identical to        or different from that used in step a1″) so as to obtain a        catalyst precursor,    -   a4″) optionally, leaving the catalyst precursor obtained in step        a3″) to mature.    -   and at least one of the organic compounds in step a1″) or in        step a3″) is selected from γ-valerolactone, 4-hydroxyvaleric        acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid.

The operating conditions described above are of course applicable in thecontext of this last-mentioned embodiment.

Process for the Preparation of a Rejuvenated Catalyst

The catalyst according to the invention may be a rejuvenated catalyst.This catalyst may be prepared by the preparation process comprising thefollowing steps:

-   -   a) bringing a regenerated catalyst containing a support based on        alumina or silica or silica-alumina, at least one component of        an element of group VIB, at least one component of an element of        group VIII and optionally phosphorus into contact with at least        one additive selected from γ-valerolactone, 4-hydroxyvaleric        acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid so        as to obtain a catalyst precursor,    -   b) drying said catalyst precursor originating from step a) at a        temperature of less than 200° C., without calcining it        subsequently.

According to step a), a regenerated catalyst is brought into contactwith at least one additive selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid, so as to obtain a catalyst precursor.

The regenerated catalyst is a catalyst that has been used as a catalystin a catalytic unit and in particular in hydrotreatment and/orhydrocracking and that has undergone at least one step of calcining, inorder to burn off the coke (regeneration). Regeneration allowscombustion of the carbon deposited on the catalyst during its industrialuse. It may be carried out by any means known to a person skilled in theart. Regeneration is generally carried out at temperatures comprisedbetween 350 and 550° C., and most often between 400 and 520° C., orbetween 420 and 520° C., or between 450 and 520° C., temperatures ofless than 500° C. often being advantageous.

The regenerated catalyst contains a support based on alumina or silicaor silica-alumina, at least one component of an element of group VIB, atleast one component of an element of group VIII and optionallyphosphorus in the respective proportions given above. Followingregeneration (calcining step), the hydrogenating function comprising theelements of group VIB and group VIII of the regenerated catalyst is inan oxide form. It may also contain dopants other than phosphorus, asdescribed above.

According to this embodiment, the contacting according to step a)comprises the following successive steps:

-   -   a1′″) impregnating a regenerated catalyst containing a support        based on alumina or silica or silica-alumina, at least one        component of an element of group VIB, at least one component of        an element of group VIII and optionally phosphorus with an        impregnating solution comprising at least one additive selected        from γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,        3-pentenoic acid or 4-pentenoic acid so as to obtain a catalyst        precursor,    -   a2′″) optionally, leaving the catalyst precursor obtained in        step a1′″) to mature.

Preferably, the contacting in step a) is carried out by impregnation ofthe regenerated catalyst with an impregnating solution comprising atleast one additive selected from γ-valerolactone, 4-hydroxyvaleric acid,2-pentenoic acid, 3-pentenoic acid or 4-pentenoic acid so as to obtain acatalyst precursor.

The additive or additives selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid may advantageously be deposited in one or more steps either byimpregnation in excess, or by dry impregnation, or by any other meansknown to a person skilled in the art.

Preferably, the additive or additives selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid is/are introduced by dry impregnation, in the presence or absenceof a solvent as described above.

Preferably, the solvent in the impregnating solution used is water,which facilitates implementation on an industrial scale.

The additive or additives selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid is/are advantageously introduced into the impregnating solutionwith the molar ratios per element of group VIB or of group VIIIdescribed above.

When in addition it is desired to introduce an additional additive (inaddition to the additive(s) selected from γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid) or a group of additional additives selected from an organiccompound containing oxygen and/or nitrogen and/or sulphur other thansaid additives, this may be introduced in the impregnating solution instep a1′″) or by an additional impregnation step at any time in thepreparation process before the final drying in step b), it beingunderstood that a calcining step is not carried out after itsintroduction. This compound is introduced in the proportions describedabove.

According to step a2′″), optionally the catalyst precursor obtained instep a1′″) is left to mature, under the maturation conditions describedabove.

According to step b) of the preparation process according to theinvention, the catalyst precursor that has optionally been maturedduring step a2′″) is subjected to a step of drying at a temperature ofless than 200° C. without a subsequent calcining step, as describedabove.

Sulphurization

Before it is used for the hydrotreatment and/or hydrocracking reaction,it is advantageous to convert the dried catalyst obtained according toany one of the methods of introduction described in the presentinvention to a sulphurized catalyst in order to form its active species.This activation or sulphurization step is carried out by the methodswell known to a person skilled in the art, and advantageously under asulpho-reducing atmosphere in the presence of hydrogen and hydrogensulphide.

At the end of step b) according to the various methods of preparation ofthe method according to the invention, said catalyst obtained istherefore advantageously subjected to a sulphurization step, without anintermediate calcining step.

Said dried catalyst is advantageously sulphurized ex situ or in situ.The sulphurization agents are H₂S gas or any other compound containingsulphur used for the activation of hydrocarbon feedstocks forsulphurization of the catalyst. Said compounds containing sulphur areadvantageously selected from the alkyl disulphides such as for exampledimethyl disulphide (DMDS), the alkyl sulphides, such as for exampledimethyl sulphide, the thiols such as for example n-butylmercaptan (or1-butanethiol), the polysulphide compounds of the tert-nonylpolysulphidetype, or any other compound known to a person skilled in the art forobtaining good sulphurization of the catalyst. Preferably the catalystis sulphurized in situ in the presence of a sulphurization agent and ahydrocarbon-containing feedstock. Very preferably the catalyst issulphurized in situ in the presence of a hydrocarbon-containingfeedstock to which dimethyl disulphide has been added.

Hydrotreatment and/or Hydrocracking Process

Finally, the invention also relates to the use of the catalyst accordingto the invention or prepared by the preparation process according to theinvention in processes for hydrotreatment and/or hydrocracking ofhydrocarbon-containing cuts.

The catalyst according to the invention, which preferably has undergonea sulphurization step beforehand, is used advantageously for thereactions of hydrotreatment and/or hydrocracking ofhydrocarbon-containing feedstocks such as petroleum cuts, cutsoriginating from coal or the hydrocarbons produced from natural gas,optionally in mixtures, or from a hydrocarbon-containing cut originatingfrom biomass and more particularly for the reactions of hydrogenation,hydrodenitrogenation, hydrodearomatization, hydrodesulphurization,hydrodeoxygenation, hydrodemetallization or hydroconversion ofhydrocarbon-containing feedstocks.

In these uses, the catalyst according to the invention, which preferablyhas undergone a sulphurization step beforehand, has improved activitywith respect to the catalysts of the prior art. This catalyst may alsoadvantageously be used during pre-treatment of the feedstocks forcatalytic cracking or hydrocracking, or hydrodesulphurization ofresidues or deep hydrodesulphurization of diesels (ULSD, Ultra LowSulphur Diesel).

The feedstocks used in the hydrotreatment process are for examplegasolines, gasoils, vacuum gasoils, atmospheric residues, vacuumresidues, atmospheric distillates, vacuum distillates, heavy fuel oils,oils, waxes and paraffins, used oils, deasphalted residues or crudeoils, feedstocks obtained from thermal or catalytic conversionprocesses, lignocellulosic feedstocks or more generally feedstocksoriginating from biomass, used alone or in a mixture. The feedstocksthat are treated, and in particular those mentioned above, generallycontain heteroatoms such as sulphur, oxygen and nitrogen, and for theheavy feedstocks, most often they also contain metals.

The operating conditions used in the processes utilizing the reactionsof hydrotreatment of hydrocarbon-containing feedstocks described aboveare generally as follows: the temperature is advantageously comprisedbetween 180 and 450° C., and preferably between 250 and 440° C., thepressure is advantageously comprised between 0.5 and 30 MPa, andpreferably between 1 and 18 MPa, the hourly space velocity isadvantageously comprised between 0.1 and 20 h⁻¹ and preferably between0.2 and 5 h⁻¹, and the hydrogen/feedstock ratio expressed as volume ofhydrogen, measured under standard conditions of temperature andpressure, per volume of liquid feedstock is advantageously comprisedbetween 50 l/l and 5,000 l/l and preferably from 80 to 2,000 l/l.

According to a first method of use, said hydrotreatment processaccording to the invention is a process of hydrotreatment, and inparticular of hydrodesulphurization (HDS) of a gasoil cut, carried outin the presence of at least one catalyst according to the invention.Said hydrotreatment process according to the invention aims to removethe sulphur-containing compounds present in said gasoil cut so as toreach the current environmental standards, namely a permitted sulphurcontent of up to 10 ppm. It also makes it possible to lower the contentsof aromatics and nitrogen in the gasoil cut to be hydrotreated.

Said gasoil cut to be hydrotreated according to the process of theinvention contains 0.02 to 5.0% by weight of sulphur. It advantageouslyoriginates from direct distillation (or straight run gasoil), from acoking unit, from a visbreaking unit, from a steam cracking unit, from aunit for hydrotreatment and/or hydrocracking of heavier feedstocksand/or from a catalytic cracking unit (Fluid Catalytic Cracking).

Said gasoil cut preferably has at least 90% of compounds the boilingpoint of which is comprised between 250° C. and 400° C. at atmosphericpressure.

The process for hydrotreatment of said gasoil cut according to theinvention is carried out under the following operating conditions: atemperature comprised between 200 and 400° C., preferably between 300and 380° C., a total pressure comprised between 2 MPa and 10 MPa andmore preferably between 3 MPa and 8 MPa with a ratio of volume ofhydrogen to volume of hydrocarbon-containing feedstock, expressed asvolume of hydrogen, measured under standard conditions of temperatureand pressure, per volume of liquid feedstock, comprised between 100 and600 liters per liter and more preferably between 200 and 400 liters perliter and an hourly space velocity comprised between 1 and 10 h⁻¹,preferably between 2 and 8 h⁻¹. The HSV corresponds to the inversecontact time expressed in hours and is defined by the ratio of thevolume flow rate of liquid hydrocarbon-containing feedstock to thevolume of catalyst loaded in the reaction unit utilizing thehydrotreatment process according to the invention. The reaction unitcarrying out the process for the hydrotreatment of said gasoil cutaccording to the invention is preferably operated in a fixed bed, amoving bed or an ebullating bed, preferably in a fixed bed.

According to a second method of use, said hydrotreatment and/orhydrocracking process according to the invention is a process forhydrotreatment (in particular hydrodesulphurization,hydrodenitrogenation, hydrogenation of aromatics) and/or hydrocrackingof a vacuum distillate cut carried out in the presence of at least onecatalyst according to the invention. Said hydrotreatment and/orhydrocracking process, otherwise called process of hydrocrackingpre-treatment or hydrocracking according to the invention, aims,depending on the case, to remove the sulphur-containing,nitrogen-containing or aromatic compounds present in said distillate cutso as to carry out a pre-treatment prior to conversion in catalyticcracking or hydroconversion processes, or for hydrocracking thedistillate cut, which would optionally have been pre-treated beforehandif required.

Very varied feedstocks can be treated by the processes for thehydrotreatment and/or hydrocracking of vacuum distillates describedabove. Generally they contain at least 20% volume and often at least 80%volume of compounds boiling above 340° C. at atmospheric pressure. Thefeedstock may be for example vacuum distillates as well as feedstocksoriginating from units for extracting aromatics from lubricating oilbases or originating from solvent dewaxing of lubricating oil bases,and/or of deasphalted oils, or the feedstock may be a deasphalted oil orparaffins originating from the Fischer-Tropsch process or any mixture ofthe feedstocks mentioned above. In general, the feedstocks have a T5boiling point greater than 340° C. at atmospheric pressure, and betterstill greater than 370° C. at atmospheric pressure, i.e. 95% of thecompounds present in the feedstock have a boiling point greater than340° C., and better still greater than 370° C. The nitrogen content ofthe feedstocks treated in the processes according to the invention isusually greater than 200 ppm by weight, preferably comprised between 500and 10,000 ppm by weight. The sulphur content of the feedstocks treatedin the processes according to the invention is usually comprised between0.01 and 5.0% by weight. The feedstock may optionally contain metals(for example nickel and vanadium). The asphaltenes content is generallyless than 3,000 ppm by weight.

The hydrotreatment and/or hydrocracking catalyst is generally broughtinto contact, in the presence of hydrogen, with the feedstocks describedabove, at a temperature greater than 200° C., often comprised between250° C. and 480° C., advantageously comprised between 320° C. and 450°C., preferably between 330° C. and 435° C., at a pressure greater than 1MPa, often comprised between 2 and 25 MPa, preferably between 3 and 20MPa, the space velocity being comprised between 0.1 and 20.0 h⁻¹ andpreferably 0.1-6.0 h⁻¹, preferably 0.2-3.0 h⁻¹, and the quantity ofhydrogen introduced is such that the volume ratio liter ofhydrogen/liter of hydrocarbon, expressed as volume of hydrogen, measuredunder standard conditions of temperature and pressure, per volume ofliquid feedstock, is comprised between 80 and 5,000 l/l and most oftenbetween 100 and 2,000 l/l.

These operating conditions used in the processes according to theinvention generally make it possible to reach conversions per pass, inproducts having boiling points of less than 340° C. at atmosphericpressure, and better still less than 370° C. at atmospheric pressure,greater than 15% and even more preferably comprised between 20 and 95%.

The processes for the hydrotreatment and/or hydrocracking of vacuumdistillates utilizing the catalysts according to the invention cover theranges of pressure and of conversion ranging from mild hydrocracking tohigh-pressure hydrocracking. By mild hydrocracking is meanthydrocracking leading to moderate conversions, generally less than 40%,and operating at low pressure, generally between 2 MPa and 6 MPa.

The catalyst according to the invention may be used alone, in a singleor in several catalyst beds in fixed-bed mode, in one or more reactors,in a so-called one-step hydrocracking system, with or without liquidrecycling of the unconverted fraction, or in a so-called two-stephydrocracking system, optionally in combination with a hydrorefiningcatalyst located upstream of the catalyst of the present invention.

According to a third method of use, said hydrotreatment and/orhydrocracking process according to the invention is advantageously usedas pre-treatment in a fluidized-bed catalytic cracking process (or FCCprocess for Fluid Catalytic Cracking). The operating conditions of thepre-treatment in terms of temperature range, pressure range, hydrogenrecycle ratio, and hourly space velocity are generally identical tothose described above for the processes for the hydrotreatment and/orhydrocracking of vacuum distillates. The FCC process may be carried outconventionally as known to a person skilled in the art under suitablecracking conditions in order to produce hydrocarbon-containing productsof lower molecular weight. A brief description of catalytic crackingwill be found for example in ULLMANS ENCYCLOPEDIA OF INDUSTRIALCHEMISTRY VOLUME A 18, 1991, pages 61 to 64.

According to a fourth method of use, said hydrotreatment and/orhydrocracking process according to the invention is a process for thehydrotreatment (in particular hydrodesulphurization) of a gasoline cutin the presence of at least one catalyst according to the invention.

In contrast to other hydrotreatment processes, the hydrotreatment (inparticular hydrodesulphurization) of gasolines must make it possible tomeet two contradictory requirements: to ensure deephydrodesulphurization of the gasolines and to limit the hydrogenation ofthe unsaturated compounds present, in order to limit the loss of octanenumber.

The feedstock is generally a hydrocarbon cut having a distillation rangecomprised between 30 and 260° C. Preferably, this hydrocarbon cut is acut of the gasoline type. Very preferably, the gasoline cut is anolefinic gasoline cut originating for example from a catalytic crackingunit (Fluid Catalytic Cracking).

The hydrotreatment process consists of bringing the hydrocarbon cut intocontact with the catalyst according to the invention and hydrogen underthe following conditions: at a temperature comprised between 200 and400° C., preferably comprised between 230 and 330° C., at a totalpressure comprised between 1 and 3 MPa, preferably comprised between 1.5and 2.5 MPa, at an hourly space velocity (HSV), defined as the volumeflow rate of feedstock with respect to the volume of catalyst, comprisedbetween 1 and 10 h⁻¹, preferably comprised between 2 and 6 h⁻¹ and at ahydrogen/gasoline feedstock volume ratio comprised between 100 and 600Nl/l, preferably comprised between 200 and 400 Nl/l.

The process for the hydrotreatment of the gasolines may be carried outin one or more reactors in series of the fixed bed type or of theebullating bed type. If the process is carried out by means of at leasttwo reactors in series, it is possible to provide a device for removingH₂S from the effluent originating from the first hydrodesulphurizationreactor before treating said effluent in the secondhydrodesulphurization reactor.

The examples given below demonstrate the significantly increasedactivity on the catalysts prepared by the process according to theinvention with respect to the catalysts of the prior art and explain theinvention but without however limiting its scope.

EXAMPLES Example 1 Preparation of the CoMoP Catalysts on Alumina withoutOrganic Compound C1 and C2 (not According to the Invention)

Cobalt, molybdenum and phosphorus are added to an alumina support havinga BET surface area of 230 m²/g, a pore volume obtained by mercuryporosimetry of 0.78 ml/g and an average diameter of the pores of 11.5 nmdefined as the median diameter by volume by mercury porosimetry andwhich is in the form of “extrudate”. The impregnating solution isprepared by dissolving molybdenum oxide (24.34 g) and cobalt hydroxide(5.34 g) at 90° C. in 7.47 g of an 85% solution of phosphoric acid inwater. After dry impregnation, the extrudates are left to mature in awater-saturated atmosphere for 12 h at ambient temperature, then theyare dried at 90° C. for 16 hours. The dried catalyst precursor thusobtained is denoted C1. Calcining the catalyst precursor C1 at 450° C.for 2 hours results in the calcined catalyst C2. The final compositionof catalysts C1 and C2 expressed in the form of oxides and referenced tothe mass of dry catalyst is then as follows: MoO₃=22.5±0.2% by weight,CoO=4.1±0.1% by weight and P₂O₅=4.0±0.1% by weight.

Example 2 Preparation of the CoMoP Catalysts on Alumina C3 and C4 (notAccording to the Invention), C5 and C6 (According to the Invention) byCo-impregnation

Cobalt, molybdenum and phosphorus are added to the alumina supportdescribed above in Example 1, which is in the form of “extrudate”. Theimpregnating solution is prepared by dissolving molybdenum oxide (28.13g) and cobalt hydroxide (6.62 g) at 90° C. in 7.88 g of an 85% solutionof phosphoric acid in water. After homogenizing the above mixture, 37.79g of citric acid was added before adjusting the solution volume to thepore volume of the support by adding water. The (citric acid)/Mo molarratio is equal to 1 mol/mol and the (citric acid)/Co molar ratio isequal to 2.8 mol/mol. After dry impregnation, the extrudates are left tomature in a water-saturated atmosphere for 12 h at ambient temperature,and then they are dried at 120° C. for 16 hours. The dried catalystprecursor thus obtained is denoted C3. The final composition of catalystC3, expressed in the form of oxides and referenced to the mass of drycatalyst, is then as follows: MoO₃=22.7±0.2% by weight, CoO=4.2±0.1% byweight and P₂O₅=3.8±0.1% by weight.

The catalyst C4 is prepared in a similar way to the catalyst C3, butafter homogenizing the metallic solution containing cobalt, molybdenumand phosphorus, triethylene glycol (TEG) is added, once again in aproportion of 1 mole per mole of molybdenum or 2.8 moles per mole ofcobalt. The catalyst C4 was left to mature in a water-saturatedatmosphere for 12 hours at ambient temperature, and then dried at 120°C. for 16 hours. The final composition of the catalyst C4, expressed inthe form of oxides and referenced to the mass of dry catalyst, is thenas follows: MoO₃=22.6±0.2% by weight, CoO=4.1±0.1% by weight andP₂O₅=3.9±0.1% by weight.

The catalysts C5 and C6 according to the invention are prepared asfollows. Cobalt, molybdenum and phosphorus are added to the aluminasupport described in Example 1, which is in the form of “extrudate”. Animpregnating solution was prepared by dissolving molybdenum oxide (78.75g) and cobalt hydroxide (18.54 g) at 90° C. in 22.08 g of an 85%solution of phosphoric acid in water. After homogenizing the abovemixture, γ-valerolactone was added to the solution, in equimolarproportions with respect to the molybdenum, i.e. 2.8 moles per mole ofcobalt, resulting in the catalyst C5. In the same way, 4-hydroxyvalericacid was added to the solution, in equimolar proportions with respect tothe molybdenum, i.e. 2.8 moles per mole of cobalt, resulting in thecatalyst C6. The volume of the solution was adjusted to the pore volumeof the support by adding water before each impregnation. After dryimpregnation, the extrudates of the two catalysts were left to mature ina water-saturated atmosphere for 12 hours at ambient temperature, andthen dried at 120° C. for 16 hours. The final composition of thecatalyst C5 expressed in the form of oxides and referenced to the massof dry catalyst is then as follows: MoO₃=22.4±0.2% by weight,CoO=4.0±0.1% by weight and P₂O₅=4.0±0.1% by weight. The finalcomposition of the catalyst C6 expressed in the form of oxides andreferenced to the mass of dry catalyst is then as follows:MoO₃=22.3±0.2% by weight, CoO=3.8±0.1% by weight and P₂O₅=4.2±0.1% byweight.

Example 3 Preparation of the CoMoP Catalyst on Alumina C7 (According tothe Invention) by Pre-impregnation

24.7 g of γ-valerolactone diluted in water, so as to obtain a solutionwith a total volume equal to the pore volume of the support, is added tothe alumina support described above in Example 1, which is in the formof “extrudate”. The solution thus formed is then dry-impregnated on thesupport before observing a maturation time of 3 hours in awater-saturated atmosphere at ambient temperature, followed by drying at120° C. for 2 hours. The modified support is then impregnated with afresh impregnating solution prepared by hot dissolution of molybdenumoxide (27.00 g) and cobalt hydroxide (6.36 g) in 7.57 g of an 85%solution of phosphoric acid in water, taking care to adjust the volumeof this last-mentioned solution to the pore volume of the previousmodified support, by adding water. After dry impregnation, theextrudates were left to mature in a water-saturated atmosphere for 3 hat ambient temperature, and then dried at 120° C. for 16 hours, to givethe catalyst C7. The final composition of the catalyst C6 expressed inthe form of oxides and referenced to the mass of dry catalyst is then asfollows: MoO₃=22.5 ±0.2% by weight, CoO=4.1±0.1% by weight andP₂O₅=4.0±0.1% by weight.

The quantities used are such that the quantity of γ-valerolactone is onemole per mole of molybdenum and 2.8 moles per mole of cobalt.

Example 4 Preparation of the CoMoP Catalysts on Alumina C8 (notAccording to the Invention) and C9 (According to the Invention) byCo-impregnation (Low Organic Compound/Mo Ratio)

Cobalt, molybdenum and phosphorus are added to the alumina supportdescribed above in Example 1, which is in the form of “extrudate”, asfor the preparation of the catalyst C3. However, during preparation ofthe impregnating solution, the citric acid/molybdenum molar ratio is inthis case equal to 0.25 mol/mol, or 0.70 mole of citric acid per mole ofcobalt. After dry impregnation, the extrudates are left to mature in awater-saturated atmosphere for 12 hours at ambient temperature, and thenthey are dried at 120° C. for 16 hours. The dried catalyst precursorthus obtained is denoted C8. The final composition of the catalyst C8,expressed in the form of oxides and referenced to the mass of drycatalyst, is then as follows: MoO₃=22.5±0.2% by weight, CoO=4.0±0.1% byweight and P₂O₅=3.9±0.1% by weight.

Cobalt, molybdenum and phosphorus are added to the alumina supportdescribed above in Example 1, which is in the form of “extrudate”, asfor the preparation of the catalyst C5. However, during preparation ofthe impregnating solution, the molar ratio of γ-valerolactone tomolybdenum was fixed at 0.25 mol/mol, i.e. 0.70 mole of γ-valerolactoneper mole of cobalt. After dry impregnation, the extrudates were left tomature in a water-saturated atmosphere for 12 hours at ambienttemperature, and then dried at 120° C. for 16 hours. The dried catalystprecursor thus obtained is denoted C9. The final composition of thecatalyst C9 expressed in the form of oxides and referenced to the massof dry catalyst is then as follows: MoO₃=22.3±0.2% by weight,CoO=4.1±0.1% by weight and P₂O₅=4.3±0.1% by weight.

Example 5 Evaluation of the Catalysts C1, C2, C3, C4 and C8 (notAccording to the Invention) and C5, C6, C7 and C9 (According to theInvention) in the HDS of Gasoil

The catalysts C1, C2, C3, C4 and C8 (not according to the invention) andC5, C6, C7 and C9 (according to the invention) were tested in the HDS ofgasoil.

Characteristics of the gasoil feedstock used: density at 15° C.: 0.8522g/cm³, sulphur: 1.44% by weight.

-   -   Simulated Distillation:

IBP 155° C. 10% 247° C. 50% 315° C. 90% 392° C. FBP 444° C.

The test is carried out in an isothermal pilot reactor with transversedfixed bed, with the fluids circulating from bottom to top. Aftersulphurization in situ at 350° C. in the unit under pressure by means ofthe gasoil for the test, to which 2% by weight of dimethyl disulphide isadded, the hydrodesulphurization test was carried out under thefollowing operating conditions: total pressure of 7 MPa, catalyst volumeof 30 cm³, temperature from 330 to 360° C., hydrogen flow rate of 24 l/hand feedstock flow rate of 60 cm³/h.

The catalytic performances of the catalysts tested are shown in Table 1.They are is expressed in degrees Celsius based on a comparative catalystselected as reference (C2): they correspond to the temperaturedifference to be applied to achieve 50 ppm of sulphur in the effluent. Anegative value indicates that the target sulphur content is reached fora lower temperature and that there is therefore a gain of activity. Apositive value means that the target sulphur content is reached for ahigher temperature and that there is therefore a loss of activity. Theresults obtained are presented in Table 1.

Table 1 clearly shows the gain in catalytic effect provided byγ-valerolactone, but also by 4-hydroxyvaleric acid. In fact, thecatalysts C5, C6 and C7 (according to the invention) have activitiesgreater than those obtained for all the other catalysts evaluated forthe same molar proportions of organic compound (1 mol/mol_(Mo)).

The gain is also maximized, for the same quantity of additive; thecatalysts C5 and C6 are more active than the catalysts C3 and C4respectively obtained with citric acid or TEG which are less active.

The activity of the catalyst C7 is still far higher than that of thebase catalyst C2 or of a dried catalyst C1 without γ-valerolactone or4-hydroxyvaleric acid.

The advantage of the catalyst according to the invention is stillsignificant at a lower proportion of organic compound, as shown by thecatalyst C9, which thus has an intrinsic effectiveness ofγ-valerolactone greater than that of the other compounds, for which itis necessary to introduce a higher proportion of compound in order toobserve a significant catalytic effect.

TABLE 1 Relative activity at iso-volume of the catalysts C1, C2, C3, C4and C8 (not according to the invention) and C5, C6, C7 and C9 (accordingto the invention) with respect to the catalyst C2 (not according to theinvention), in the hydrodesulphurization of gasoil Method of Catalystintroducing (comparative the organic or according compound to theOrganic compound used (post-/co-/pre- Heat invention) and molar ratio/Moimpregnation) treatment HDS activity C1 (comp) none N/A Dried Base +1.1° C. 120° C. C2 (comp) none N/A Calcined Base C3 (comp) Citricacid-1.0 CO Dried Base − 3.1° C. 120° C. C4 (comp) TEG-1.0 CO Dried Base− 5.3° C. 120° C. C5 (inv) γ-valerolactone-1.0 CO Dried Base − 7.3° C.120° C. C6 (inv) 4-hydroxyvaleric acid- CO Dried Base − 6.8° C. 1.0 120°C. C7 (inv) γ-valerolactone-1.0 PRE Dried Base − 6.2° C. 120° C. C8(comp) Citric acid-0.25 CO Dried Base − 2.2° C. 120° C. C9 (inv)γ-valerolactone-0.25 CO Dried Base − 4.4° C. 120° C.

The invention claimed is:
 1. A catalyst comprising a support based onalumina or silica or silica-alumina, at least one element of group VIII,at least one element of group VIB, at least one additive that isγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid, and phosphorus, the phosphorus content being0.1 to 20% by weight expressed as P₂O₅ with respect to the total weightof the catalyst and the ratio of phosphorus to the element of group VIBin the catalyst is greater than or equal to 0.05.
 2. The catalystaccording to claim 1, having a content of the element of group VIB of 5to 40% by weight expressed as oxide of the metal of group VIB withrespect to the total weight of the catalyst and a content of the elementof group VIII of 1 to 10% by weight expressed as oxide of the metal ofgroup VIII with respect to the total weight of the catalyst.
 3. Thecatalyst according to claim 1, having a molar ratio of the element ofgroup VIII to the element of group VIB in the catalyst of 0.1 to 0.8. 4.The catalyst according to claim 1, having a total content of additive(s)γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid, or 4-pentenoic acid of 1 to 35% by weight with respect to thetotal weight of the catalyst.
 5. The catalyst according to claim 1,which additionally contains an organic compound other than the additiveγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid, said organic compound containing oxygen and/ornitrogen and/or sulphur.
 6. The catalyst according to claim 5, in whichthe organic compound is a compound comprising one or more of a carboxyl,alcohol, thiol, thioether, sulphone, sulphoxide, ether, aldehyde,ketone, ester, carbonate, amine, nitrile, imide, oxime, urea or amidefunctions.
 7. The catalyst according to claim 6, in which the organiccompound is triethylene glycol, diethylene glycol,ethylenediaminetetraacetic acid, maleic acid, citric acid,dimethylformamide, bicine, or tricine.
 8. The catalyst according toclaim 1, in which the support contains from 0.1 to 50% by weight ofzeolite.
 9. The catalyst according to claim 1, that is at leastpartially sulphurized.
 10. A process for the hydrotreatment and/orhydrocracking of hydrocarbon-containing cuts, comprising subjecting saidcuts to hydrotreatment and/or hydrocracking, conditions in the presenceof a catalyst according to claim
 1. 11. A process for the preparation ofa catalyst according to claim 1 comprising: a) bringing at least onecomponent of an element of group VIB, at least one component of anelement of group VIII, at least one additive that is γ-valerolactone,4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoic acid or 4-pentenoicacid and phosphorus into contact with a support based on alumina orsilica or silica-alumina, or bringing a regenerated catalyst containinga support based on alumina or silica or silica-alumina, at least onecomponent of an element of group VIB, at least one component of anelement of group VIII and phosphorus into contact with at least oneadditive γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,3-pentenoic acid or 4-pentenoic acid, so as to obtain a catalystprecursor, b) drying said catalyst precursor originating from a) at atemperature of less than 200° C., without calcining it subsequently. 12.The process according to claim 11, in which a) comprises the following:a′) impregnating a support based on alumina or silica or silica-aluminawith at least one solution containing at least one element of group VIB,at least one element of group VIII, at least one additive that isγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid and phosphorus so as to obtain a catalystprecursor.
 13. The process according to claim 11, in which a) comprisesthe following: a1) impregnating a support based on alumina or silica orsilica-alumina with at least one solution containing at least oneelement of group VIB, at least one element of group VIII and phosphorusin order to obtain an impregnated support, a2) drying the impregnatedsupport obtained in a1) at a temperature of less than 200° C. in orderto obtain a dried impregnated support, and calcining the driedimpregnated support in order to obtain a calcined impregnated support,a3) impregnating the dried and optionally calcined impregnated supportobtained in a2) with an impregnating solution comprising at least oneadditive that is γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoicacid, 3-pentenoic acid or 4-pentenoic acid so as to obtain a catalystprecursor, a4) optionally, leaving the catalyst precursor obtained ina3) to mature.
 14. The process according to claim 11, in which a)comprises the following: a1′) preparing a support comprising at leastone additive that is γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoicacid, 3-pentenoic acid or 4-pentenoic acid and at least one part ofphosphorus, a2′) impregnating the support obtained in a1′) with animpregnating solution comprising at least one element of group VIB, atleast one element of group VIII and phosphorus so as to obtain acatalyst precursor, a3′) optionally, leaving the catalyst precursorobtained in a2′) to mature.
 15. The process according to claim 11, inwhich a) comprises the following: a1″) by co-impregnation, bringing asolution containing at least one element of group VIB, at least oneelement of group VIII, at least one organic compound containing oxygenand/or nitrogen and/or sulphur, and phosphorus into contact with asupport based on alumina or silica or silica-alumina so as to obtain animpregnated support, a2″) drying the impregnated support originatingfrom step a1″) at a temperature of less than 200° C., without calciningit subsequently, in order to obtain a dried impregnated support, a3″)bringing the dried impregnated support originating from step a2″) intocontact with a solution of an organic compound containing oxygen and/ornitrogen and/or sulphur, identical to or different from that used instep a1″), so as to obtain a catalyst precursor, a4″) optionally,leaving the catalyst precursor obtained in step a3″) to mature, and atleast one of the organic compounds in step a1″) or in a3″) isγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid.
 16. The process according to claim 11, inwhich a) comprises the following: a1′″) impregnating a regeneratedcatalyst containing a support based on alumina or silica orsilica-alumina, at least one component of an element of group VIB, atleast one component of an element of group VIII and phosphorus with animpregnating solution comprising at least one additive that isγ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid, 3-pentenoicacid or 4-pentenoic acid so as to obtain a catalyst precursor, a2′″)optionally, leaving the catalyst precursor obtained in a1′″) to mature.17. The process according to claim 11, in which the total molar ratio ofthe γ-valerolactone, 4-hydroxyvaleric acid, 2-pentenoic acid,3-pentenoic acid or 4-pentenoic acid additive(s) to the element(s) ofgroup VIII is 0.1 to 5.0 mol/mol.